• PNF and Movement
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• v.19 no.2
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• pp.279-285
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• 2021

Purpose: This study aimed to develop new digital navicular drop test (ND-NDT) equipment and to determine its validity and reliability. Methods: A total of 24 healthy male and female adults, who fully understood the purpose of the study and gave consent to participate in the study, were selected as participants. The NDT and ND-NDT were conducted in the dominant foot of the participants in a random order. For the NDT, the position of the navicular bone was marked with a pen first; then, the height of the navicular bone from the ground was measured in both sitting and standing positions. For the ND-NDT, after the sticker-type reflection markers were attached to the position of the navicular bone, the height of the navicular bone from the ground was measured in both sitting and standing positions. To assess the validity of the diagnostic tests, the same examiner measured the height of the medial longitudinal arch (MLA) three times in both the sitting and standing positions. To assess the inter-rater reliability of the ND-NDT, three examiners, in a random order, attached the sticker-type reflection markers to the position of the navicular bone and then measured the height of the MLA in both positions. Results: In the sitting position, the Pearson correlation coefficient (r) between the two diagnostic tests was very high (r = 0.97) and statistically significant. In the standing position, the Pearson correlation coefficient (r) between the two tests was 0.95, which was also statistically significant. The ICC_2,1 values in the sitting and standing positions were 0.93 and 0.95, respectively, indicating significantly high inter-rater reliability. Conclusion: The ND-NDT equipment showed very high diagnostic validity, as well as excellent inter-rater reliability, indicating the clinical usefulness of the equipment as a diagnostic system for confirming pes planus.

• Journal of the Semiconductor & Display Technology
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• v.21 no.1
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• pp.95-102
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• 2022

Since the organic light-emitting diodes (OLEDs) have been widely investigated as next-generation displays, it has been successfully commercialized as a flexible and rollable display. However, there is still wide room and demand to improve the device characteristics such as power efficiency and lifetime. To solve this issue, there has been a wide research effort, and among them, the internal and the external light extraction techniques have been attracted in this research field by its fascinating characteristic of material independence. In this study, a micro-nano composite structured external light extraction layer was demonstrated. A reactive ion etching (RIE) process was performed on the surfaces of hexagonally packed hemisphere micro-lens array (MLA) and randomly distributed sphere diffusing films to form micro-nano composite structures. Random nanostructures of different sizes were fabricated by controlling the processing time of the O₂ / CHF₃ plasma. The fabricated device using a micro-nano composite external light extraction layer showed 1.38X improved external quantum efficiency compared to the reference device. The results prove that the external light extraction efficiency is improved by applying the micro-nano composite structure on conventional MLA fabricated through a simple process.

• Korean Journal of Radiology
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• v.20 no.1
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• pp.94-101
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• 2019

Objective: To investigate the efficacy of motion-correction algorithm (MCA) in improving coronary artery image quality and measurement accuracy using an anthropomorphic dynamic heart phantom and 256-detector row computed tomography (CT) scanner. Materials and Methods: An anthropomorphic dynamic heart phantom was scanned under a static condition and under heart rate (HR) simulation of 50-120 beats per minute (bpm), and the obtained images were reconstructed using conventional algorithm (CA) and MCA. We compared the subjective image quality of coronary arteries using a four-point scale (1, excellent; 2, good; 3, fair; 4, poor) and measurement accuracy using measurement errors of the minimal luminal diameter (MLD) and minimal luminal area (MLA). Results: Compared with CA, MCA significantly improved the subjective image quality at HRs of 110 bpm (1.3 ± 0.3 vs. 1.9 ± 0.8, p = 0.003) and 120 bpm (1.7 ± 0.7 vs. 2.3 ± 0.6, p = 0.006). The measurement error of MLD significantly decreased on using MCA at 110 bpm (11.7 ± 5.9% vs. 18.4 ± 9.4%, p = 0.013) and 120 bpm (10.0 ± 7.3% vs. 25.0 ± 16.5%, p = 0.013). The measurement error of the MLA was also reduced using MCA at 110 bpm (19.2 ± 28.1% vs. 26.4 ± 21.6%, p = 0.028) and 120 bpm (17.9 ± 17.7% vs. 34.8 ± 19.6%, p = 0.018). Conclusion: Motion-correction algorithm can improve the coronary artery image quality and measurement accuracy at a high HR using an anthropomorphic dynamic heart phantom and 256-detector row CT scanner.

• Transactions of the Korean Society of Automotive Engineers
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• v.14 no.4
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• pp.139-148
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• 2006

Valve train is one of the important noise sources in idling engines. Valve train noise comes mostly from two different impacts. One is the impact between cam and tappet at the beginning of the valve open period, which is an important source of impulsive noise of valve trains. The other is the impact between valve and valve seat at the closing of the valve open period. In case of mechanical lash adjusters, it is very difficult to control the initial impact. In this paper, we designed various types of cam profiles, especially in the opening ramp design, and investigated the effect of cam profiles on the magnitude of the initial impact. The effects that some cam design parameters have on the impulsive noise are also observed.

• ETRI Journal
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• v.31 no.3
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• pp.327-329
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• 2009

In a network, broadcasting is the dissemination of a message from a source node holding a message to all the remaining nodes through a call. This letter proposes a one-to-all broadcasting algorithm in the Petersen-torus network PT(n, n) for the single-link-available and multiple-link-available models. A PT(n, n) is a regular network whose degree is 4 and number of nodes is $10n^2$, where the Petersen graph is set as a basic module, and the basic module is connected in the form of a torus. A broadcasting algorithm is developed using a divide-and-conquer technique, and the time complexity of the proposed algorithm approximates n+4, the diameter of PT(n, n), which is the lower bound of the time complexity of broadcasting.

• Journal of the Korean Ceramic Society
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• v.34 no.4
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• pp.337-342
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• 1997

This paper describes the design and evaluation of new type piezoelectric bimorph actuator that shows much large mechanical response than those conventional types. The bimorph actuator has modified structure combined with the multilayer actuator(MLA) and the composite multilayer actuator called "Moonie". The design and performancean alysis of bimorph actuator are carried out with Finite Element Method (FEM). Theoretical calculation results show that the generating force and displacement of Moonie-modified bimorph actuator can be improved by about 130% and 150%, respectively. The overshooting and ringing phenomena of the bimorph can be effectively restrained by the pseudo step electric field having a rising time coincied with a period of the fundamental vibration mode of the bimorph.e bimorph.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.11a
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• pp.372-375
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• 2003

MCA deflection control is a important technology for the development of MEMS applications. In this study, deflection analysis at the MLA/Si diaphragm was investigated by Finite Element Method. Analysis of Si diaphragm combined with MCA has been implemented into the ANSYS (Solid5 and Solid45). On the basis of this structure, deflection versus MCA number of layers has been modelled and MCA/Si contact area characteristics with different diaphragm conditions were analyzed. Consequently, it is expected that fabrication technology of MCA/Si diaphragm could be usefully applied for the fabrication process of high-performance piezoelectric MEMS devices.

• Proceedings of the Korea Information Processing Society Conference
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• 2012.04a
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• pp.402-405
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• 2012

문서와 문서간의 유사도들 측정하는 방법 은 크게 지문법 (fingerprint)을 이용한 방법과 서열 정렬(sequence alignment)알고리즘을 이용한 방법이 있다. 두 방법은 각각 속도와 정확도라는 장점을 가지고 있다. 다단계정렬(MLA, Multi-Level alignment))는 이러한 두 방법을 조합하여 탐색 속도와 정확도 사이의 비중을 사용자가 결정할 수 있도록 하기 위한 방법이다.[1] 다단계 정렬은 두 문서를 단위 블록(basis block)로 나누고 블록 간의 벡터를 비교하여 유사도를 측정하게 되는데, 본 연구에서는 초성 추출 및 어간 추출을 통해 단위 블록의 벡터를 빠른 시 간에 생성하고 비교하는 방법과 다단계 탐색을 통해 정확도를 유지하면서 빠르게 유사도를 측정하는 방식에 대해 설명한다. 실험결과 제안 방법을 통해 다단계 정렬 방법을 이용한 대용량 문서 비교의 속도가 2 배 이상 빨라짐을 보인다.

• Current Optics and Photonics
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• v.8 no.3
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• pp.239-245
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• 2024

This paper proposes single logarithmic amplification (single-LA) and deep learning (DL)-based fixed-threshold on-off keying (OOK) detection for free-space optical (FSO) communication. Multilevel LAs (MLAs) can be used to mitigate intensity fluctuations in the received OOK signal by their nonlinear gain characteristics; however, it is ineffective in the case of high scintillation, owing to degradation of the OOK signal's extinction ratio. Therefore, a DL technique is applied to realize effective scintillation compensation in single-LA applications. Fully connected (FC) networks and fully connected neural networks (FCNN), which have nonlinear modeling characteristics, are deployed in this work. The performance of the proposed method is evaluated through simulations under various scintillation effects. Simulation results show that the proposed method outperforms the conventional adaptive-threshold-decision, single-LA-based, MLA-based, FC-based, and FCNN-based OOK detection techniques.

• IMMUNE NETWORK
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• v.1 no.2
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• pp.162-169
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• 2001

Background: Nitric oxide (NO), a cytotoxic molecule is produced in various tissues including tumor cells during interleukin-2 (IL-2) therapy . Lymphokine-activated killer (LAK) cells are induced during IL-2 therapy, and have cytotoxic activity against tumor cells. The current study investigated the effects of NO synthesized in target cells or exposure of target cells to NO on the sensitivity of target cells to LAK cell cytotoxicity. Methods: Cytotoxicity was measured using 4 h chromium release assays. LAK cells which were induced by a 4 day incubation of BALB/c mouse splenocytes with IL-2 (6,000 IU/mL) were employed as effector cells. RD-995 skin tumor cells originated from a C3H/HeN mouse were employed as target cells. NO synthesis in target cells was induced by a 24 h incubation of RD-995 cells with $IFN{\gamma}$ (25 U/mL), TNF (50 U/mL) and IL-1 (20 U/mL). S-nitrosyl acetylpenicillamine (SNAP), an NO donor, was used to expose target cells to NO. $N^G$-monomethyl-L-arginine (MLA) and carboxy-PTIO were added during cytotoxicity assays to inhibit NO synthesis, and to scavenge NO produced by target cells, respectively. Results: Sensitivity of NO-producing RD-995 cells to LAK cell cytotoxicity was decreased by addition of MLA and carboxy-PTIO during cytotoxicity assays. However, the two reagents had no effect on the sensitivity of non-NO-producing RD-995 cells. Pretreatment of RD-995 target cells with SNAP increased the sensitivity in comparison with untreated cells. Conclusions: Sensitivity of target cells to LAK cell cytotoxicity is increased by target cell NO synthesis or exposure to NO. Further studies are needed to evaluate whether these in vitro results have relevance to in vivo phenomena.